The role of key messages has assumed an almost common-sense status within public relations campaigns. This research examines award-winning campaigns to explore what assumptions and understandings underpin the use of key messages by public relations practitioners. It was envisaged this would help explicate an aspect of practice that is seemingly widespread and ingrained. The findings report in four thematic areas that emerged from the data: environment, development, attributes and context. The concept of a congested and contested messaging environment was found to be the key driver behind the use of key messages. Practitioners saw well-crafted key messages as having the power to cut through the environment to achieve specific outcomes and positively position organisations. The study concludes that although a transmission model/media effects theoretical perspective was evident, practice could also be conceptualised as a social constructionist endeavour in that practitioners worked to create versions of social reality to achieve organisational goals. Further, it was also found that practitioners might benefit from a deeper understanding of how people receive, engage with, and process information in terms of campaign message design and evaluation.